Spur drive for regenerator-type heat exchanger

ABSTRACT

A rimless rotary heat exchanger of the disc type having ceramic plugs buried in the peripheral face thereof. These plugs have depressions frictionally containing spring metal clips which have means in the form of a sharp spur that engage and deform the material of a drive ring gear positioned about the peripheral face of the heat exchanger.

Elmite @ttee mm Stockton 51 Sept. 26, 1972 54] SPUR DRIVE FORREGENERATOR- 3,430,687 3/1969 Wardale ..165/8 TYPE HEAT EXQHANGE3,586,096 6/1971 McLean ..165/8 [72] Inventor: Thoma-s Rowe Stockton,Ann Arbor, 3,177,735 4/1965 Chute ..74/446 X Mlch' PrimaryExaminer-Albert W. Davis, Jr. [73] A i F d M t Company, Dem-born,Attorney-John R. Faulkner and Keith L. Zerschling Mich.

[221 Filed: Dec. 31, 1970 [57] ABSTRACT [21] Ap l. N 103,215 A rimlessrotary heat exchanger of the disc type having ceramic plugs buried inthe peripheral face I thereof. These plugs have depressions frictionallycon- [52] US. Cl ..165/8, 74/446, 64/15 R, [aining pring metal clipswhich have means in the 64/27 R, 165/10 form of a sharp spur that engageand deform the [51] Int. Cl ..F28d 19/04 material of a drive ring gearpositioned about the [58] Field of Search..l65/8, 10; 64/15 R, 27 R, 27L; p riph face of the heat exchanger- [56] I References Cited 7 Claims,4 Drawing Figures I UNITED STATES PATENTS 3,401,741 9/1968 Paluszny eta1. ..165/8 PATENTEDsms m2 SHEET 2 [IF 2 m (if saua DRIVE FORREGENERATOR-TYPE rmx'r xcmucsa BACKGROUND AND SUMMARY OF THE INVENTIONThis invention relates to a rotary heat exchanger of the type that maybe used in an automotive gas turbine engine and more particularly to arimless ceramic rotary regenerator of the disc type which is driven bymeans of an annular metal ring gear.

In US. Pat. No. 3,401,741, there is shown a ceramic rotary heatexchanger drive assembly which comprises I a' plurality of ceramic-likeplug inserts positioned in the peripheral face of a ceramic matrix whichcomprises the heat exchanger. Each of the ceramic-like plug inserts hasa recess which receives a portion of a spring clip. These spring clipshave tabs or hooks which are positioned in engagement with a flangeextending laterally in both directions from the ring gear.

The presentinvention provides an improvement over the structuredescribed above and shown in U.S. Pat. No. 3,401,741. In the invention,a plurality of spring clips are positioned in the space between an outerperipheral face of an annular ceramic heat exchange matrix of the axialflow type and the inner surface of a surrounding annular driving meansor ring gear which is employed to drive the annular ceramic matrix.These spring clips have means engaging the matrix for preventingrelative circumferential movement of each of the spring clips withrespect to the matrix in the intended direction of rotation, and thespring clips also include means engaging and deforming the material ofthe inner surface of the ring gear for preventing relativecircumferential movement of the ring gear with'respect to the springclip in the intended direction of rotation of the ring gear.

In the preferred form of the invention, the inner surface of the ringgear adjacent the outer peripheral surface of the ceramic matrix isprovided with an annular groove which maybe of generally V-shaped crosssection, and the spring clip is provided with a sharp apex or spur whichfits within this annular grooveand indents or deforms the material ofthe ring gear to provide a driving relationship between the ring gearand the plurality of spring clips. The spring clips are also preferablypositioned within recesses in a plurality of circumferentially spacedceramic plugs located within the outer portion of the annular ceramicmatrix.

As a result of the above-described structure, the drive load from thering gear is evenly distributed to the annular ceramic matrix whichcomprises the heat exchanger. The annular driving means or ring gear isautomatically located axially with respect to the annular ceramic matrixby virtue of the sharp apices of the spring clips fitting within thecomplementary shaped groove in the ring gear. In addition, no closespacing requirements need be met at final assembly. The provision of theannular groove which receives the sharp apices or spurs on the springclips provides a structure where this engagement may occur anywherewithin the 360 circumference of the annular ring gear. Thus,

there is no structure that needs to be provided which has closedimensional tolerances on the ring gear with respect to the ceramicmatrix and spring clips. It is also readily apparent that the springclips of the present invention are reusable and may be used with anytype of ring gear assembly. Moreover, the resultant vector forces of thespring load of the spring clips and the driving load components can bearranged to pass through the geometric center of the ceramic plugs so asto eliminate any sheer loading of the cement bond at the interface ofthe ceramic matrix and these plugs.

An object of the present invention is the provision of an uncomplicatedand inexpensive driving connection between an annular driving means anda ceramic rotary heat exchanger.

Another object of the invention is the provision of an inexpensive anduncomplicated drive arrangement between an annular drive gear and aceramic heat exchange matrix which is easily assembled and has no closedimensional tolerances with respect to any of the components employed.

Other objects and attendant advantages of the present invention may bemore readily realized as the specification is considered in connectionwith the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of arotary disc-type heat exchanger embodying the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1, with parts brokenaway and in section;

FIG. 3 is a sectional view taken along the lines 3-3 of FIG. 2; and

FIG. 4 is a perspective view of one of the spring clips of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings inwhich like reference numerals designate like parts throughout theseveral views thereof, there is shown in FIG. 1 a disclike rotaryregenerator or heat exchanger of the type commonly used in automotivegas turbine engines. It has a matrix 10 that consists of a plurality ofradially alternating flat and corrugated ceramic strips 12 and 14,respectively. These strips are brazed or otherwise secured together toprovide radially sealed axial flow fluid or gas passages 16. This matrixhas an inner aperture 18 and is center mounted on a stationary shaft 20by suitable bearing means not shown.

The matrix has a uniform cross section from hub aperture 18 to the outerperipheral surface 22. At this outer peripheral surface, a thin coat ofcement is applied around the circumference of the matrix to radiallyseal the outermost axial flow passages. For clarity, this thin cementcoating is shown in exaggerated form.

A conventional narrow metallic ring gear 26 comprises the driving memberfor rotatably driving the matrix 10. In general, it is secured to thematrix by a number of flexible spring clips 28. These clips arepreloaded upon assembly of the ring gear around the matrix tofrictionally engage recessed or scalloped portions 30 provided in eachof a plurality of ceramic plugs 32 buried within the outer surface ofthe matrix 10 and preferably positioned about the periphery of thematrix with equal spacing between them.

More specifically, the outer cemented face of the matrix 10 has aplurality of circumferentially spaced small recesses or depressions 36of shallow extent and preferably semi-circular in cross section. Each ofthese recesses is filled or plugged with a ceramic material which isthen machined to provide the recess or depression 30 conforming to theshape of the inner portion of the flexible metallic spring clips 28. a

The spring clips 28'are generally U-shaped in cross section as shown inFIG. 2. Each clip has a body portion '40'which is generally planar andrectangular in shape. The free end of this body portion has anupturned-flange 42 which is complementary in shape to one endof therecess or depression The other leg 44 v of thegenerally U- shaped springclip 28 is preferably taper contoured to equalize bending stressthroughout the clip so as to achieve'a maximum and constant radial:sprin'gload regardless of dimensional a'sharp spur or apex 46 which ispreferably positioned at an obtuse anglewith respect to the leg 44.

The annular drive meansvor ringgear 26 has a plurality of spur teeth 48positioned on the outer periphery thereof. for engagement with a piniondrive gear (not shown). The inner surface 50 of thering gear or annulardrive means 26 is provided with an annular groove 52 which preferably iscomplementary in shape to the sharp spur or apex 46 of the spring clip28.

, The material which forms the sharp spur or apex 46 is'harder than thematerial which forms the ring gear 26, so that the sharp spur or apex.46 will indent or deform the material of the ring gear 26 duringassembly and drive operations. 4 I

In assembly of the ring gear 26, the matrix 10, and the spring clips 28,the spring clips may be positioned about the inner periphery orsurface'SO ofthe ring gear 26 with the apices or sharp spurs 46 of thespring clips 28 positioned in the groove. 52. The spring clips 28 arethen compressedso that they may be properly positioned within thedepressions or recesses 30in the ceramic plugs 32. As can readily beappreciated by an inspection of FIGS. 2, 3 and 4, the spacingbetween-the legs 44 and 40 and more particularly-between the upturned.flange 42 and the apex or spur 46 of the-spring clip 28 when it is inthe free or unstressed position as shownin FIG. 4.is much greater thanit is when the clip is in the assembledpositionas shown in FIGS. 2 and3. Consequently, large radial forces are developed in the spring clipwhich cause thespur or apex 46 to deform the material of the ring gear26 or, stated otherwise, the apex or spur 46 indents or digs into thematerial of the ring gear 26. Additionally, when tangential orcircumferential forces are applied to the spur or apex 46 upon rotationof the ring gear in a counter clockwise direction as shown in FIG. 2,these tangential or circumferential forces cause a further deformationor indentation of the material of the ring gear 26.

It can be readily appreciated that the groove 52 positioned in the innersurface 50 of the ring gear or annular drive means 26 may be V-shaped asshown, or it also may be rectangular or of any other desired contourwhich would properly mate with the shape of the sharp apex or spur46.-Likewise, this apex or spur- 56 could be shaped somewhat differentlythan as shown in the drawings to conform to the other shapes of theannular grooves in the inner surface of the ring g ar. It can also beappreciated that multiple grooves and multiple apices may be provided onthe inner surface of the ring gear and on the spring clips,respectively.

Although not shown in the drawing, the outer peripheral surface 22 ofthe matrix :10 could be provided with a peripheral groove having thesame width as the planar portion of the spring clips 28. Consequently,if the matrix 10 encounters resistance to rotation, the spring clips 28,can ride out of the recesses depression 30 in the ceramic plugs 32 onthe outer peripheral surface 22 from recess to recess in the ceramicplugs 32.

.Thus, the present invention provides an extremely uncomplicated andinexpensive drive means for a ceramic type rimless rotary heatexchanger. Additionally, the present invention has the advantage, amongothers, that close dimensional tolerances need not be maintained betweenany of the component parts of the heat. exchange drive assemblyincluding the ring gear, the spring clips and the rotary heat exchangematrix itself.

Iclaim: v g

l. A drive assembly for a rimless rotary regenerator of the disctypecomprising a disc-like rotatable annular ceramic matrix of the axialfluid flow type, and rotatable drivemeans cooperating with a peripheralface of saidmatrix to rotate said matrix, said face having a pluralityof circumferentially spaced recesses positioned I and said body portionof said spring clip is positioned in said recess.

3; The combination of claim 2 in which each of said spring clips isshaped substantially in a U with the apex end thereon facing in acircumferential direction opposite to the direction of rotation of saidrotatable drive means.

4. The combination'of claim 3 in whichsaid spur tip end portion of saidspring clip extends from one end of the U and is indented into thematerial of said rotatable drive means at an obtuse angle with respectthereto when viewed in the direction of intended rotation of said drivemeans.

5. The combination of claim 4 in which said spring clip is tapered fromsaid spur tip end portion to said body portion.

6. A drive assembly for a rimless rotary regenerator of the disc typecomprising a disc-like rotatable annular ceramic matrix of the axialflow type, a ring gear positioned around said disc-like rotatableannular ceramic matrix, said ringgear having an inner surface positionedin radial spaced relationship to the outer peripheral face of saidmatrix, the outer surface of said ring gear having a plurality of gearteeth positioned therein, a plurality of spring clips positioned in thespace between the outer peripheral face of said matrix and the innersurface of said ring gear, each of said spring clips having meansengaging said matrix for preventing relative circumferential movement ofsaid and deforming the material of the inner surface of said ring gearfor preventing relative circumferential move- 7. The combination ofclaim 6 in which said last mentioned means comprises a sharp spur formedon said spring clip extending in a direction opposite to the inment ofsaid ring gear with respect to said spring clip in 5 tended dlrecuon ofrotation of sad rmg gear' the intended direction of rotation of saidring gear.

1. A drive assembly for a rimless rotary regenerator of the disc typecomprising a disc-like rotatable annular ceramic matrix of the axialfluid flow type, and rotatable drive means cooperating with a peripheralface of said matrix to rotate said matrix, said face having a pluralityof circumferentially spaced recesses posiTioned therein, a ceramic-likeplug means positioned in each of said recesses, a spring clip having abody portion engaging each of said ceramic-like plug means, saidrotatable drive means having an annular groove positioned therein inradially spaced relationship with respect to the peripheral face of saidmatrix, each of said spring clips having a spur tip end portionpositioned in said annular groove and indented into the material of saidrotatable drive means.
 2. The combination of claim 1 in which each ofsaid ceramiclike plug means has a recess positioned therein and saidbody portion of said spring clip is positioned in said recess.
 2. Thecombination of claim 1 in which each of said ceramic-like plug means hasa recess positioned therein and said body portion of said spring clip ispositioned in said recess.
 3. The combination of claim 2 in which eachof said spring clips is shaped substantially in a U with the apex endthereon facing in a circumferential direction opposite to the directionof rotation of said rotatable drive means.
 3. The combination of claim 2in which each of said spring clips is shaped substantially in a U withthe apex end thereon facing in a circumferential direction opposite tothe direction of rotation of said rotatable drive means.
 4. Thecombination of claim 3 in which said spur tip end portion of said springclip extends from one end of the U and is indented into the material ofsaid rotatable drive means at an obtuse angle with respect thereto whenviewed in the direction of intended rotation of said drive means.
 4. Thecombination of claim 3 in which said spur tip end portion of said springclip extends from one end of the U and is indented into the material ofsaid rotatable drive means at an obtuse angle with respect thereto whenviewed in the direction of intended rotation of said drive means.
 5. Thecombination of claim 4 in which said spring clip is tapered from saidspur tip end portion to said body portion.
 5. The combination of claim 4in which said spring clip is tapered from said spur tip end portion tosaid body portion.
 6. A drive assembly for a rimless rotary regeneratorof the disc type comprising a disc-like rotatable annular ceramic matrixof the axial flow type, a ring gear positioned around said disclikerotatable annular ceramic matrix, said ring gear having an inner surfacepositioned in radial spaced relationship to the outer peripheral face ofsaid matrix, the outer surface of said ring gear having a plurality ofgear teeth positioned therein, a plurality of spring clips positioned inthe space between the outer peripheral face of said matrix and the innersurface of said ring gear, each of said spring clips having meansengaging said matrix for preventing relative circumferential movement ofsaid spring clip with respect to said matrix in the intended directionof rotation of said matrix and means engaging and deforming the materialof the inner surface of said ring gear for preventing relativecircumferential movement of said ring gear with respect to said springclip in the intended direction of rotation of said ring gear.
 6. A driveassembly for a rimless rotary regenerator of the disc type comprising adisc-like rotatable annular ceramic matrix of the axial flow type, aring gear positioned around said disc-like rotatable annular ceramicmatrix, said ring gear having an inner surface positioned in radialspaced relationship to the outer peripheral face of said matrix, theouter surface of said ring gear having a plurality of gear teethpositioned therein, a plurality of spring clips positioned in the spacebetween the outer peripheral face of said matrix and the inner surfaceof said ring gear, each of said spring clips having means engaging saidmatrix for preventing relative circumferential movement of said springclip with respect to said matrix in the intended direction of rotationof said matrix and means engaging and deforming the material of theinner surface of said ring gear for preventing relative circumferentialmovement of said ring gear with respect to said spring clip in theintended direction of rotation of said ring gear.
 7. The combination ofclaim 6 in which said last mentioned means comprises a sharp spur formedon said spring clip extending in a direction opposite to the intendeddirection of rotation of said ring gear.
 7. The combination of claim 6in which said last mentioned means comprises a sharp spur formed on saidspring clip extending in a direction opposite to the intended directionof rotation of said ring gear.